Figure 94-36

Left posterior fascicular block with RBBB.
A. No MI.
B. Anteroseptal MI (note Q wave in V2).
C. Inferior MI (note ST-segment elevation and T-wave inversion in leads 11 and AVF with slight ST-segment depression in lead in lead 1). The difference between A and C are not very marked since pure LPFB may produce an almost abnormal Q wave in the inferior leads. Conversely, this conduction disturbance, by producing an initial depolarization wave front oriented superiorly, is capable of decreasing the depth(thus normalizing) the abnormal Q-wave characteristic of inferior MI in leads11, 111, and AVF.